Struct contents reference from a non-struct array object... I have an error when I run below Matlab code, however I am running this code on the parallel pool. MATLAB2017b

function D = SvmSegm_extract_all_class_features_nofiles(exp_dir, img_name, mask_type, class_feats, delete_local_feats)
   DefaultVal('delete_local_feats', 'true');

     img_name = {img_name};

     [meas_req, needs_shape, figure_ground, the_pars] = SvmSegm_get_measurements_required(class_feats);   

     %
     % Histograms of gradients
     %

     parfor i=1:numel(meas_req)
         filename = [exp_dir 'MyMeasurements/' mask_type '_' class_feats{i} '/' img_name{1} '.mat'];
         if(~needs_shape(i))
             filename = [exp_dir 'MyMeasurements/' meas_req{i} '/' img_name{1} '.mat'];
             if(~exist(filename, 'file'))
                 SvmSegm_extract_measurements_new(meas_req{i}, img_name, exp_dir, inf);
             end
         else
             if(~exist(filename, 'file'))
                 SvmSegm_extract_measurements_on_masks(mask_type, meas_req{i}, the_pars{i}, img_name, exp_dir);
             end
         end
     end

     %
     % Bag of words
     %
     parfor i=1:numel(class_feats)
         if(the_pars(i).isbow)
           SvmSegm_get_bow_like_histograms_multiple_segments(mask_type, meas_req{i}, {figure_ground{i}}, img_name, exp_dir);
         end
     end

     if(delete_local_feats)
         for i=1:numel(class_feats)
             if(the_pars(i).isbow)
                 filename = [exp_dir 'MyMeasurements/' meas_req{i} '/' img_name{1} '.mat'];
                 if(exist(filename, 'file'))
                     delete([exp_dir 'MyMeasurements/' meas_req{i} '/' img_name{1} '.mat']);
                 end
             end
         end
     end

     for i=1:numel(class_feats)
         var = load([exp_dir 'MyMeasurements/' mask_type '_' class_feats{i} '/' img_name{1} '.mat']);
         D{i} = var.D;
     end
  end

...............................................................

Error using SvmSegm_extract_all_class_features_nofiles (line 37)
Struct contents reference from a non-struct array object.

Error in cpmc>get_features (line 185)
    D_2 = SvmSegm_extract_all_class_features_nofiles(exp_dir, img_name, mask_type, feat_types(recog_feats_in),
    delete_local_feats);

Error in cpmc (line 132)
    D = get_features(exp_dir, img_name, segm_pars.name, masks, segment_measurements);

Error in cpmc_example (line 33)
   [masks, scores] = cpmc(exp_dir, img_name);

Answer 1

[Walter Roberson]

The line

                   SvmSegm_extract_measurements_on_masks(mask_type, meas_req{i}, the_pars{i}, img_name, exp_dir);

believes that the_pars is a cell array, but the line

         if(the_pars(i).isbow)

believes that the_pars is a non-scalar struct.

Those two lines are only compatible if SvmSegm_extract_measurements_on_masks uses assignin('caller') to overwrite the_pars, or if SvmSegm_extract_measurements_on_masks is certain to error() before continuing.

[ALTAF KHAN]

thank you #Walter Roberson